This week the Billboard Hot 100, the magazine’s 55-year-old singles chart, takes a evolutionary step by incorporating YouTube plays into its formula. The move comes just in time for Baauer’s song “Harlem Shake,” the latest viral video phenomenon, which will make its debut at No. 1 this week thanks to the change.

“Harlem Shake,” a bass-heavy hip-hop track with no lyrics beyond a few samples, got little mainstream attention when it was released in May as a free download. But this month its popularity exploded on YouTube, as thousands of fans uploaded videos of themselves dancing — some might say simply flailing — along to the song. By last week more than 4,000 videos were going up each day.

Imagine: ”Chocolate Rain” topping the charts. If this policy had been implemented a few years ago … it could’ve happened. Also: As “Harlem Shake” was released on an independent label, it makes it the third independently-released song to top the charts in history, the second being the song it replaced: Macklemore & Ryan Lewis’ “Thrift Shop.” (ht Ethan Klapper)